The primary goal of this research program is the understanding of how the interaction between nerve tissues and sensory experience influence neuronal development especially the development of neuronal dendrites. This research, as a continuation of my initial studies, will be conducted with laboratory rats. I will focus our study initially on the medial superior olivary (MSO) nucleus, which represents the first binaural ascending convergence center in the rat's brain. I shall analyze quantitatively the effects of modifications of aural experience during early stages of development on the morphology of dendrites and physiological properties of the MSO neurons. Rats will be raised in the laboratory under various kinds of reduced acoustic sensory experience, i.e., monaural or binaural ear plug. Single unit recordings will be conducted in the MSO nucleus of anesthetized rats (control and experimental). Other rats will be sacrificed for anatomical observation of the morphology of MSO neurons (Golgi impregnated). The results of this study are expected to provide important concepts with regard to the plasticity of dendritic development and some insights into the mechanisms that underlie neuronal morphogenesis.